Method and mechanism for web splitting



May 1l, 1965 .1. D. PARKER E'rAl. 3,182,874

METHOD AND MECHANISM FOR WEB SPLITTING Filed Nov. 27, 196s 4 sheets-sheet 1 N Y- --Y-f Y f/ :i 1' E-r'z. g I W 'v, f I w I l S Q i ze; E I

N E EL. INVENTORS 'u l 'Joseph D. Pczflef I W/efd. M1212 TeffgL. obzoafz M wf t TTORNEYS May 11 1955 J. D. PARKER ETAL 3,182,874

l METHOD AND MECHANISM FOR WEB SPLITTING 4 Sheets-Sheet 2 Filed Nov. 27, 196s QUJOOU WUJOCQ S wf j W. Z www mfg; T voa mpwm n. LR @www @Wm/bw@ w NMHI,

May 11,1965 J. D.' PARKER ETAL 3,182,874

METHOD AND MECHANISM FOR WEB SPLITTING Filed Nov. 27, 1965 4 Sheets-Sheet 5 May 11, l965 J. D. PARKER ETAL. 3,182,874

METHOD AND MECHANISM FOR WEB SPLITTING 4 Sheets-Sheet 4 Filed Nov. 27, 1963 IN VE N T0 R5 Jose D. Parker Wagef CZ Mik Te .Dobmz zzsajsozz ffy E YSl United States Patent() 3,182,874 METHOD ANI) MECHANISM FR WEB SPLITTING Joseph D. Parker and Terry Leonard Dobratz, Beloit, Wis., David R. Gustafson, Rockton, Ill., and Walter Chin Mill, South Beloit, Wis., assignors to Beloit Corporation, Beloit, Wis., a corporation of Wisconsin Filed Nov. 27, 1963, Ser. No. 326,450 14 Claims. (Cl. 22S-3) The present invention relates to improvements in a mechanism and method for separating a web into layers.

More particularly the invention relates to an improved method and mechanism for separating layers of a web passing the web through the nip formed between a pair of chilled Vcylindrical rolls, cooling the surfaces of the rolls to a temperature below the freezing point of the moisture in the web, maintaining a predetermined pressure inA said nip, rotating the rolls at a uniform surface speed so that as the web isdrawn into the nip its surfaces will freeze and adhere to the surfaces of the rolls, and separating the web from the roll surfaces on the olf running side of the nip.

The separation of a paper sheet into layers is important in Vthe analysis of the characteristics of paper structure and the effectiveness of paper manufacturingprocesses. An important and frequently determined characteristic Vof paper structure is the transverse distribution of fines in the paper. While earlier investigations were concerned only with the specific components of the tine mate- ICC A still further object of the invention is to provide an improved web splitting mechanism whereinv the relative thicknesses of layers separated from the web can be uniformly controlled.

A further object of the invention is to provide an improved sheet splitting mechanism receiving individual sheets of paper and splitting the sheets accurately.

Techniques have heretofore been developed to obtain the parallel sectioning of paper but have not been wholly satisfactory. These have included scraping off layers with a razor blade, grinding off layers with fine Carborundum paper, peeling off successive layers with adhesive tape and by parallel sectioning with a microtome. The present arrangement is capable of high speed and continuous parallel sectioning of paper webs and sheets and is capable of accurately controlling the thickness of these sections.

The present invention involves a mechanism and a process in whicha wetted paper web is divided in the plane of the sheet by progressively freezing the outer surface of the sheet to smooth surfaces in a dynamic process and splitting the sheet in an interior plane in a zone which has not been frozen by the advancing ice rial, the distribution of theiines and filler material to the depth of the sheet has been recognized as being important. It has been discovered that the specific filtration resistance is a sensitive index of the specic surface of `the paper and hence, the iines content of a pulp. By measuring the distribution of specific filtration resistance 'through the depth of a sheet, an analysis ofthe distribution of fine material can be made and this can include the actual distribution of cellulosic nes and debris. By splitting a sheet in layers of controlled thickness the specific filtration resistance of the layers can be determined. p v

Splitting of sheets can also be used `for determining other characteristics of paper, such as for example the permeation of ink into the sheet and printing such as in the analysis of printed newsprint. The permeability of the printing is an index of the impermeability of surface coating. By separation of a sheet of paper into layers, the function and effect of various sections of a paper making machinein producing two-sidednessV eects can be determined, lsuch as are caused by the headbox setting, table make-up, slice discharge velocity, wire speed and other factors.

The separation of multi-ply sheets is required in various Y manufacturing operations such as in the paper making industry wherein multi-ply sheets are made of different types of stock and must be separated before re-pulping. Separationof the layers of laminated sheets is required for recovery of plastic lrnmaterial adhered to a paper web backing, and the separation of layers'of web isre arrangement which effects a saving in time and accomplishes uniform separation. A

Another object of the inventionlis to provide an imv proved web splitting mechanism which is capable of conmercial uses.

fronts created due to the temperature of the sheet being reduced starting at its outer surfaces.

Other objects, advantages and features will become more apparent with the teaching of the principles of the present invention in connection with the disclosure of the preferred embodiments thereof in the specification, claims and drawings, in which: y

FIGURE l is a side elevational view of a web splitting mechanism embodying the principles of the present invention;

. FIGURE 2 is a top plan'view of the mechanism of FIGURE 1;

FIGURE 3 is a side elevational View of a sheet splitting mechanism embodying the principles of the present invention;

FIGURE 4 is a top plan View of the mechanism of vFIGURE 3; and

FIGURE 5 is a fragmentary sectional View taken sub stantially along line V-V of FIGURE 4.

On the drawings: y The method and apparatus shown in FIGURES 1 through 5 embodies freezing the sides of a wetted or water-soaked sheet tothe surfaces of two metal rolls, cooled below the freezing temperature of water and rotating with a pressure or spring loaded nip. The wet sheet, introduced into the roll nip, is split internally into two frozen sections on the Voutgoing side of the nip with the rolls being rotated at 'a rate which isrelated to the temperatures of the roll surfaces so that the splittingoccurs as a dynamic process in which the interior plane of the splitting takes place in a Vrzone which has not been frozen by the advancing ice fronts produced by the splitting ',rolls. The split sections are doctored from the rolls and "the split sections in turn can be re-split until the sections split. The rolls are cooled indicated by the arrowed lines. The web W may be of any type which is to be split into layers, such as a paper xweb which is in plies or laminated of different types of -stock which must be separated so that the different layers are used in separate pulping batches. The web also may e be of a layer of pulp and a layer of plastic or other sheeting. y t web will be known and it Vcan be predetermined'as Vto the nip pressure and `roll temperature requiredv to cause the `In each instance the moisture content .of the 3 surfaces of the web to freeze and adhere to the surfaces of the rolls 1G and 11.

The temperature of the rolls and 11 and the speed of rotation thereof are interdependent factors which are related so that a roll surface speed is chosen which gives the web adequate time in the nip to freeze to the roll surface. As higher speeds of operation are sought, lower temperatures are provided for more rapid freezing. The moisture content ofv the web is also a factor and the nip pressure must be such that adequate contact pressure is afforded between the roll surface and web so that the moisture within the web will be in surface contact with the roll to form frozen crystals which adhere to the roll surface.

The roll 10 is vsupported on end bearings 12 and 13, FIGURE 2, and the roll 11 is supported on end bearings 14 and 15.

As shown in FIGURES l and 2 the rolls are supported Von a stand 16 which has upright supports 17 for the bearings 12 and 1-3. Also on the stand are end supports 18 for the bearings 14 and 15. The support 17 is shown rigidly secured atjits base to the stand 16, and the supports 18 are pivoted attheir lower ends so as to permit a slight difference in spacing between the aXis of the rolls as the nip pressure is changed.

For driving the rolls a drive gear -19 is driven by suitable power means, not shown, which may be provided with a variable speed control so as to obtain the nip speed desired. The drive gear 19 drives gears 20 and A21 respectively connected to shafts 22 and 23Y for the rolls 10 .and 11. Flexible drives 24 and 25 are provided to accommodate slight changes in the relative'positions of the axes of the rolls 10 and 11.

Suitable means are provided for biasing the rolls to-V gether to control the nip pressure, as shown by turnbuckles 2.6 and 27 which have the usual ,central adjuster with travelling nuts at the ends connected to the uprights y17 and 18.

The web W passes down into the nip N and its split forming layersV W-1 and W-2 which are separated from the rolls '10 and 11 at a location following the olf-running side of the nip N. As illustrated adjustable doctor blade mechanisms .2o and 27 are provided having a doctor blade edge which engages the surface of the rolls 10 and 11 and separates the Vweb layers W-1 and W-Z. The layers are received by suitable means such as wind-up rolls.

lFor cooling the rolls 10 and 11 to a temperature below the freezing temperature of the moisture in the web W, refrigerating liquid suchas brine is directed into the rolls through refrigerating liquid supply lines 28 and 29. The liquid ows into the hollow rolls 10 and 11 through distribution pipes 30 and 31 which extend coaxially into the rotating rolls 10 and 11. The pipes Sil and 61 may emit the refrigerant liquid at their open ends or may be pro- Y vided with perforations along their length.

For removing the refrigerating liquid return lines 34 and 35 are provided.Y The supply and return lines connect to the rolls-10 and 11 through rotary fittings 32 and -33 which permit the continual recirculation of liquid during rotation of the rolls'10 and 1-1.

The returning refrigerating liquid is led through suit# able piping to refrigerating coolers 36 and 37. The liquid Vis circulated such as by pumps d@ and 41. The lines are lprovided with temperature controls 3S and 39 which maintain the Vtemperature inthe rollsltb and `11 at the desired degree."l Automatic temperature controls may be` pro- --vided byproviding surface contacting temperature meas- 1uring devices, not shown, connectedtothe temperature controls 38 and 39.

Control of the relative thicknesses of the layers which adhere'to the rolls -10 Vand -11 can be regulated by the rela tive temperatures of the rolls. If the porosity of the layers Y of the web is different it may be necessary lto have la n Ytemperature differential between the rolls 1G and 11 for plished, and a heavier layer is to be removed by one roll than the other, its temperature may be lowered so that the depth of freezing is deeper than for the other roll. Temperature control may also be used where the layers removed are different such as where a plastic layer is to be removed from the layer of paper web.

It is also contemplated that the moisture of the web W may be controlled such as by providing sprays for the web in advance of the nip N. For example where a plastic sheet is to be removed from the paper web, it may be desirable to meisten the surface of the plastic such as by positioning a light vapor spray adjacent the plastic surface in advance of the nip N.

In operation a continuously travelling web W is fed from a supply into the nip N between the rolls 1) and 11 which are cooled to a temperature below the freezing point of the moisture in the web. The layers of the web will adhere to the surface of the rolls and will split, and the layers W- and W-2 are separated from the rolls such as by doctor blades l26 and 27. Various separating means may be used and the drawings illustrate Vpivotally supported doctor blades mounted on pivots 2da and 27a and weighted so that the separating edges of the blades will be maintained in contact with the roll surfaces due to counterweights `Ztb and 27h of the blade assemblies.

In the arrangement of FIGURES 3 through 5 splitting rolls 5t? and 51 are mounted parallel to provide a nip N therebetween. The roll Sti is supported on journals 52 and 52a at the ends mounted'in suitable bearings 541 and 55. The roll 51 is supportedron journals k53 and 53a carried in bearings 54a and 55a.

rSince Athe rollsare of substantially identical construction, only the roll 50 need be described in detail and is shown in FIGURE 5 as being hollow. In some instances the chamber 56 therein may be filled with a heat transfer liquid such as methyl alcohol. Within the chamber is a heat transfer cooling liquid coil 57 and liquid is circulated therein by supply and return lines 61 and 62 which eX- tend through the hollow extension 63 of the'journal 52. Methyl alcohol may be used as the heat transfer liquid withinthe coil 57. The rolls are driven by a sprocket 5S, driven by a chain `63, :FIGURES 3 and 4, which is driven by a drive sprocket 64. The rolls rotate at the same speed being interconnected by gears 59 and 59a.

The interior chamber 56 of the roll is closed by a seal 60 permitting rotation and preventing leakage of the liquid therein. Temperature determinationnand temperature control of the roll can be determined by heat sensitive member 64 projecting into the chamber 56 engaging the coil at een and measuring the temperature of the coolant leaving the coil 57, land provided with a temperature indicator. The member 64 may also be arranged to measure the temperature of the space within the roll, or the roll surface. Temperature indicators may beprovided for each of the rolls and maintain the same by controlling the flow of coolant through the coil 57, and the coil for the other roll 51, through suitable valving arrangements, not shown, and if desired automatic control mechanism may be provided.

As above described, the `temperature of the rolls is re lated to their speed of rotation so that freezing of the water within the rolls progresses to the center by the time the sheet leaves the nip so that the sheet is split internally along a plane at a zone which has-not been frozen between the advancing ice fronts from the two Vroll surfaces. By maintaining one roll colder than the other it is possible to strip off very thin layers' from the main sheet or, in other words, toV divide the sheet into layers ofY different thicknesses. Y Y

The rolls have a polished surface preferably with a nish of about A10 microinches, The rolls are of stainless steel. The rolls are loaded so that a nip pressure of about 3.0 pounds per lineal inch is achieved although this may Y' be varied. The web is scraped offwith a doctor blade 'obtaining the proper'splitting of the web at the correctV location. f Also, if a hon-uniform Vsplitis to b e accomwhich may beuof ordinary steel creping doctor stock, and

Ythe doctors are loaded against the rollsV with about 4 pounds per lineal inch nip pressure. It is important to keep the doctor blades sharp, and so long as they remain sharp the frozen sections are doctored off the rolls cleanly and will curl into small cylinders above the doctor blades, with the doctors being shown at 84 and 85.

Exit temperatures of the coolant from the coils 57 are preferably held between 25 and 30 F. The temperature of the roll surface is substantially the same as the liquid exit temperature in most installations. tions the temperatures should be controlled so that the sur- :face of the roll is between 25? and 30 F., although lower temperatures can be used in special circumstances. For example in splitting a full thickness of a sheet of newsprint, a linear roll surface speed of 1.8 inches per second may be used with a coolant exit temperature of 28 F. and to split a one-half section of newsprint into onefourth sections, the speed must be increased to 3.6 inches per second. To split a one-fourth section into one-eighth sections, a speed of 7.2 inches per second is used. Thus withA a fixed temperature the proper splitting effect may be obtained by controllingthe speed of rotation of the rolls. Where extra thick sheets are used or special grades, the temperatures may be lowered to F.

It is important that the sheets are thoroughly and uniformly wetted. This may be accomplished by storing them in adamp atmosphere andinitial moisture contents should be in the range of 40% V-to ,60% water. Heavily sizedl sheets may be prepared by` soaking them in a dilute caustic solution before the water ris added to yield a more uniformly wetted sheet for splitting. The nip pressure is preferably in the range of 1.0 to 5.0 pounds per linear inch and it is importantthat the loading be uniform across the face of the rolls. Too much nip pressure will cause crushing of the wet sheet. i

As shown in FIGURESS through 5, the bearings 54a and 55a for the roll 51 are movably mounted in a bell crank support 67 supported on a pivot support shaft 66 on the frame 65. Nip pressure is obtained by applying a force to a lower arm of the bell crank 67 by a coil compression spring 68 compressed by an adjustable nut 69 on a pivotally mounted bolt 70 on the frame 65.

The mechanism for receiving the portion of the sheet split by the roll 51 is also carried on the bell crank 67.

For all installa-` The drawings and specification present a detailed disclosure of the preferred embodiments Aof the invention, and it is to be understood that the invention is not limited to the specilic forms disclosed, but covers all modifica- The sheets are received by trays 79 and 80 located immediately following the sharp doctor blades 84 and 85.

The trays are pivoted on bosses 81 and 82 with the tray 80 ybeing pivoted by `a pivot handle 83. The trays are held in place, and the doctor blades are held against the rolls and 51 by tension springs 88 and 89.

Cleaning doctors 86 and 87 engage the rolls following the sheet separating doctors, and these cleaning doctors remove particles of pulp which may adhere to the surface of the rolls land remove ice crystals which may tend to form. The cleaning doctors are held against the rolls by 1 doctors -are pivoted pivotal arm 71 mounted on a shaft '73;y The sheet S will be swung with its leading edge up into the nip N when the arm 71 i s pivoted by movingfahandle 74 downwardly. The tray 72 is of alength so that the leading edge ofl the sheet S projects to be received by the nip N. The tray is releasably held in its lowered position by a latch includ- Ving a latch member 76 on the tray and a pivotal latch f' member held in latching position by a torsion spring 77. `The latch is pivotallyr supported on a bracket 78.

Thus it will be seen that we have provided an improved web splitting mechanism which meets-the objectives, ad-4 vantages and features above set forth. The device may be in theforrn of separate platens or other members having web orvsheet engaging surface areasrand the illustrated VVfeeding the sheets, a feeding tray 72is supported on a f arrangement utilizing rolls is desired because of being able to obtain continuous operation at relatively high surfaceV speeds. n t e tions, changes and alternative constructions and methods falling within the scope of the principles taught by the invention.

We claim as our invention: l. A mechanism for separating layers `of laminated web comprising,

a pair of chilled cylindrical rolls forming a web receiving nip therebetween, means for cooling the surfaces of said rolls to a temperature below the freezing point of moisture in the web, means for rotating the rolls so that the web will be drawn into said nipand opposed surfaces will be frozen to the surfaces of the rolls, and means for removing the separated layers of the web from the rolls after the web has passed through the nip. 2. A mechanism for separating layers of laminated web comprising,

a pair of chilled cylindrical rolls forming a web receiving nip therebetween, means for cooling the surfaces of said rolls to a temperature below the freezing point of moisture in the web, means for rotating the rolls sothat the web will be drawn into said nip and opposed surfaces will be frozen to the surfaces of the rolls, and rst and second doetoring `blades each engaging one of the rolls and separating the layer of .the web frozen to the surface thereof on the off running side off the nip. v 3. A mechanism for separating layers of laminated web comprising,

members having first and second smooth surfaces for engaging the outer surfaces of a web,-4 cooling means for cooling the surfaces to a temperature below the freezing pointof moisture in the web so that the web will adhere to said surfaces and separate into layers when the surfaces are separated, and means for removing the separated layers from said surfaces. 4. A mechanism for separating layers of laminated weby comprising,

a pair of chilled cylindrical rolls forming a web receiving nip therebetween, means for cooling the surfaces of said Arolls to a temperature below the freezing point of moisture in the web, means for rotating the rolls so that the web will'be drawn into `said nip and opposed surfaces will .be frozen to the surfaces of the'rolls, means for adjusting the nip pressu-rebetween the rolls for determining the pressure between thei web and surfaces of the rolls, and means for removing the separated layers of the web from the rolls after lthe web has passed through ,the nip. l 5. The method o-f separating layers -of alaminated lweb comprising the steps,

engaging the outer surfaces of the web with surface areas cooled below the freezing point of moisture in the web for a period of time suicient for the moisture to freeze to the smooth surface areas,

separating the surface areas to draw apart the layers a moist sheet between a pair of metal i allowing each side of the moist sheet to be `frozen to its respective metal member,

and parting the metal member thereby splitting the sheet.

7. The method of separating layers of a laminated moist web comprising the steps,

passing the web through a nip formed between a pair of smooth rolls rotated `at the same surface speed and urged together to form a pressure nip,

cooling the rolls to below the freezing lpoint of the moisture in the web and freezing the sur-faces of the web to the surfaces of the rolls,

and separating the separated layers of the web adhered to the surface of the rolls from the surface of the rolls following the nip.

8. A'mechanism for separating layers of laminated moist paper web comprising, k

iirst and second smooth surfaced hollow rolls forming a pressure nip therebetween,

a stand for said rolls having a xed first support for the first roll having roll support bearings and a second support for the second roll having roll support bearingsrand being movable for adjustingl nip pressure,

a turnbuckle adjuster at the ends of the rolls connected between the supports for drawing the supports together and increasing nip pressure,

a drive for said rolls for driving the rolls at the same surface speed,

flexible drive shaft means extending between the drive Y and each of said rolls for accommodatingadjustment of the rollaxes with adjustment of nip pressure,

irst and second doctor blades respectively for the rolls positioned after the olf running side of the nip for` separating layers of the web `from the rolls,

a refrigerant inletleading into each of said rolls for cooling the rolls below the fneezing temperature of moisture in the web, g f

and a refrigerant outlet for `each of the rolls so that the refrigerant can be recirculated and the rolls maintained at the temperature below the freezing point of the moisture in the web.

9. A mechanism for separating layers of laminated web comprising, Y

first and second chilled cylindrical rolls forming a web receiving nip therebetween,

means for rot-ating the rolls so that the web will pass through said nip, Y

means for cooling the rolls to a temperature below the freezing point of the moisture in the web so that the web'will freeze and adhere to the surfaces of the rolls,

means yfor removing the separated layers of the web from the rolls after the nip, and means for controlling the relative temperatures of said first and second rolls so that the'thickness of the layers ofthe web adhering to each of said rolls into layers of concooling each of said surface areas to a predetermined temperature and decreasing the temperature of one `of said areas relative 4to the other area yfor increasing the thickness of layer which will adhere tol said one area, and separating said areas for splitting the web. 11. A mechanism for separating layers of sheets comprising, v

a pair of chilled cylindrical rolls forming a sheet receiving nip therebetween, means `for cooling the surface of said rolls to a ternperature below the freezing point of moisture in the sheet, Y means for rotating the rolls so that the Vsheet will be drawn into said nip and opposed surfaces will be frozen to the surfaces of the rolls, means for removing the separated layers of the sheet from the rolls after the sheet has passed through the nip, and means for carrying a sheet up into the nip. 12. The method of separating layers of a sheet comprising,

cooling the exposed surfacesvof the sheet .to a temperature below the freezing point of moisture in the sheet so that the temperature drops beginning at the outer surfaces thereof so that ice yfronts progress inwardly from theY` outer surfaces of the sheet, and immediately separating the sheet drawing the layers outwardly when the ice fronts reach a zone intermediate the outer surfaces of the sheet but before the ice fronts meet. 13. The method of continually separating layers of a sheet progressively along the sheet which comprises,

chilling the sheet from the outer surfaces thereof in a cooling zone which is moved progressively along lthe sheet so that an ice front advances inwardl;l into the sheet and longitudinally along the sheet, and progressively splitting the sheet along an inner zone progressing longitudinally with said zone located between the advancing ice fronts. 14. The method of separating layers ofV a sheet vcomprising, the steps of wetting the sheet and obtaining substantially uniform moisture content throughout, passing the sheet through a nip formed between a pair of smooth rolls rotated Vatthe same surface speed and urged together to form a pressure nip with the rolls being cooled below the freezing point of the moisture, v and separating the separated layers of the sheet on the outgoing side of the nip between the rolls.

lReferences Cited by the Examiner UNITED STATES .PATENTS ANDREW R. JUHASZ, Pmrrry Examiner. 

14. THE METHOD OF SEPARATING LAYERS OF A SHEET COMPRISING, THE STEPS OF WETTING THE SHEET AND OBTAINING SUBSTANTIALLY UNIFORM MOISTURE CONTENT THROUGHOUT, PASSING THE SHEET THROUGH A NIP FORMED BETWEEN A PAIR OF SMOOTH ROLLS ROTATED AT THE SAME SURFACE SPEED AND URGED TOGETHER TO FORM A PRESSURE NIP WITH THE ROLLS BEING COOLED BELOW THE FREEZING POINT OF THE MOISTURE, AND SEPARATING THE SEPARATED LAYERS OF THE SHEET ON THE OUTGOING SIDE OF THE NIP BETWEEN THE ROLLS. 